This invention relates to the structural bonding of pieces of material, and, more particularly, to an approach for adhesively bonding and then, at a later time, debonding the pieces.
The joining of pieces of materials is an operation common to nearly all manufacturing processes. One important type of joining is structural joining, where the joint must be sufficiently strong to bear the structural loadings carried by the pieces themselves. For many years, the most common approach to structural joining was the use of point fasteners, such as rivets, screws, and bolts.
More recently, the use of structural adhesives has become more common, and many parts for defense and commercial applications are now bonded together with adhesives. While an adhesive normally is not as strong at a single location as a point fastener, the adhesive spreads the structural load carried by the joint over a large area so that a lower strength adhesive is easily sufficient. A structural adhesive joint has the additional advantages that the joint is sealed by the adhesive, the joint is normally resistant to environmental attack by water and many chemicals, and the joint has reduced incidence of stress concentrations that often lead to fatigue failure in pieces joined by point fasteners.
However, adhesive bonding has a major shortcoming when compared to joining with removable fasteners such as screws, bolts, and some types of rivets. It may be desirable to join the pieces together for some purpose, such as testing, and then later separate the pieces, as for inspection of the interior of the structure. Such joining and separation are readily accomplished with many removable fasteners, but not with structural adhesive bonds.
Because of the advantages of adhesive bonding, there is a need for an approach that permits bonding of pieces with structural adhesives and later debonding the pieces, without damaging the pieces that are bonded or sensitive apparatus located nearby. The present invention fulfills this need, and further provides related advantages.